On the morning of 5 May 1996, Qantas Airlines reported "smoke" over Sumatra near Sorikmarapi to just above 10 km altitude. However, in a satellite pass about 2 hours earlier there was no evidence of an eruption.

CVGHM reported increased seismicity from Sorik Marapi during 1-12 December and white plumes rose 40-50 m above the summit. CVGHM raised the Alert Level on 12 December from 1 to 2 (on a scale of 1-4) based on seismic data.

Temperatures increased at two fumaroles during August: from 104 to 197°C at the N crater, and from 95 to 108°C at Sibangor Julu. White fume was almost continuously present, rising to ~100 m above the crater. In late August, seismic activity began to increase. By early September, near-surface earthquakes averaged ~7/day and deeper, tectonic earthquakes averaged ~40/day.

Normal activity continued in late July, with a weak gas plume reaching 5-10 m above the crater. The temperature of the crater solfatara was 185-190°C, while two surrounding solfataric areas measured 108-110°C and 97-115°C. Twenty-nine tectonic earthquakes (but no volcanic shocks) were recorded.

On the morning of 5 May 1996, Qantas Airlines reported "smoke" over Sumatra near Sorikmarapi to just above 10 km altitude. However, in a satellite pass about 2 hours earlier there was no evidence of an eruption.

Basic Data

Volcano Types

Rock Types

Tectonic Setting

Subduction zoneContinental crust (> 25 km)

Population

Within 5 kmWithin 10 kmWithin 30 kmWithin 100 km

203
1,469
90,257
1,831,957

Geological Summary

Sorikmarapi is a forested stratovolcano with a 600-m-wide summit crater containing a crater lake and substantial sulfur deposits. A smaller parasitic crater (Danau Merah) on the upper SE flank also contains a crater lake; these two craters and a series of smaller explosion pits occur along a NW-SE line. Several solfatara fields are located on the eastern flank. Phreatic eruptions have occurred from summit and flank vents during the 19th and 20th centuries.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Synonyms

Sorieq Berapi | Seret Berapi | Sorikmerapi

Cones

Feature Name

Feature Type

Elevation

Latitude

Longitude

Kulabu

Cone

0° 41' 0" N

99° 29' 0" E

Craters

Feature Name

Feature Type

Elevation

Latitude

Longitude

Jurang Siunik

Crater

Merah, Danau

Crater

2063 m

Thermal

Feature Name

Feature Type

Elevation

Latitude

Longitude

Sibangor Julu
Sibanggor Djulu

Thermal

Photo Gallery

Sorikmarapi, seen here from the west, is a forested stratovolcano with a steep-sided, 600-m-wide summit crater containing a crater lake and substantial sulfur deposits. Another crater lake is located on the upper SE flank and several small explosion craters occur within the main crater and on the outer flanks. Small explosive eruptions have been documented from summit and flank vents in the 19th and 20th centuries.

Photo by Tom Casadevall, 1987 (U.S. Geological Survey).

Sorikmarapi volcano rises above older mountains that have impeded its growth to the north. The truncated summit contains a crater lake and a chain of smaller NW-SE-trending craters. Historical eruptions have been recorded from both summit and flank vents since the 19th century.

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).

Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.

Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.